This research is directed toward defining the role of octopamine in the vertebrate nervous system, as a possible neurotransmitter or neurohumoral agent. As a means of elucidating its role, morphological localization studies, biochemical and metabolic analyses, and physiological studies will be used. Complicating indirect interactions with the sympathetic nervous system will be screened out by the use of a sympathetically denervated preparation of the rat submandibular glands, where octopamine and its synthetic enzyme, dopamine-beta-hydroxylase, remain after sympathetic terminals have degenerated. The amine and the enzyme will be localized by autoradiography and immunofluorescence-histochemistry. Metabolic interconversions and turnover of octopamine will be studied in vivo and in vitro, along with the effects of octopamine on the qualitative and quantitative composition of salivary gland secretions in vitro. It is hoped that a new system for neurotransmitter action will be developed that will help elucidate mechanisms of synaptic specificity, connectivity and modulation.